1. Field of the Invention
The present invention relates to a vehicle ceiling structure, and in particular, to a vehicle ceiling structure capable of preventing an excessive stress from concentrating on an assist grip at expansion of a curtain shield air bag, and improving the appearance of a ceiling interior material around the assist grip.
2. Description of the Related Art
For example, a conventionally-known vehicle ceiling structure as shown in FIG. 6A includes a ceiling interior material 103 that covers a curtain shield air bag 102 with a terminal side 103a; an assist grip 111 attached to a body panel 112 through attachment holes 109 formed in the ceiling interior material 103; and attachment portions 117 provided at the assist grip 111, the attachment portions 117 being in contact with the outer circumferences of the respective attachment holes 109 in a surface of the ceiling interior material 103 in a vehicle cabin side (Refer to, for example, Japanese Unexamined Patent Publication No. 2002-362283).
The above-mentioned patent document discloses, as shown in FIG. 6B, that a plurality of slits 120 extending outward from the edge of each of the attachment holes 109 is formed in the ceiling interior material 103. When the terminal side 103a of the ceiling interior material 103 opens toward the vehicle cabin side at expansion of the curtain shield air bag 102, the slits 120 split off to increase the diameter of the attachment holes 109, resulting in that the ceiling interior material 103 escapes from the attachment portions 117 of the assist grip 111.
However, according to the technique disclosed in the patent document, the ceiling interior material 103 has the plurality of slits 120 extending outward from the edge of the attachment holes 109. When the plurality of slits 120 does not uniformly split at expansion of the curtain shield air bag 102, the ceiling interior material 103 may caught with the attachment portions 117 of the assist grip 111, causing an excessive force to concentrate on the assist grip 111. Further, when the length of the slits 120 is set to be long to sufficiently increase the diameter of the attachment holes 109, for example, as shown in FIG. 7, at use of the assist grip 111, the slits 120 on the surface of the ceiling interior material 103 in the vehicle cabin side are seen from the vehicle cabin side, degrading the appearance around the assist grip 111.